In this project, various aspects of immunological reactions to haptens on autologous carriers are being investigated. The conjugates are NIPMGG, DNPMGG and DNBSO3NA ion. They are used as tolerogens as well as immunogens. The responses they elicit are analyzed by measuring in vitro DNA synthetic response and antibody synthesis. DNA synthesis is assessed by measuring the incooperation of H3-thymidine in the DNA of the dividing cells. Antibody is measured by ammonium sulphate precipitation test or by plaque-forming cells. The aspects being studied are a) the role of the thymus in priming to these antigens. Thymectomized, sham thymectomized and nude mice are used in these studies; b) the role of the thymus in the induction of hapten specific tolerance; c) the effect of graft versus host reaction on induction of hapten tolerance; d) in vitro activation of T-cells from mice immunized with these antigens. Peritoneal exudate cells are being used in these studies; e) the influence of age on the induction of hapten specific tolerance.